Deterministically electing an active node

ABSTRACT

Methods, apparatuses, and systems for deterministically electing an active node. The methods, apparatuses, and systems include a node retrieving active processor information from a shared storage node, becoming active if the active processor information indicates the retrieving node, attempting to communicate with a second node indicated by the active processor information if the active processor information does not indicate the retrieving node, and the retrieving node becoming active if the second node does not communicate with the retrieving node.

BACKGROUND

Server management provides tools for management of multiple integratedservers. A server management system may include software or firmwarethat manages operation of those servers, performs administrative tasks,and provides remote troubleshooting ability. Such server management hasbeen implemented utilizing Intelligent Platform Management (IPMI), whichis a standard that provides interconnection between servers. IPMI mayfurthermore utilize multiple chassis management modules to manageoperation of the integrated servers. One chassis management module mayoperate as an active chassis management module while one or more otherchassis management modules may operate as standby chassis managementmodules. The standby chassis management modules may take the place ofthe active chassis management module if the active chassis managementmodule is removed or fails. It is desirable, however, to minimizeflip-flopping or alternation of active chassis management module betweentwo or more operational chassis management modules.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, wherein like reference numerals are employedto designate like components, are included to provide a furtherunderstanding of deterministic chassis management module selection, areincorporated in and constitute a part of this specification, andillustrate embodiments of deterministic chassis management moduleselection that together with the description serve to explain theprinciples thereof.

In the drawings:

FIG. 1 is a block diagram of an embodiment of a method of deterministicchassis management module selection;

FIG. 2 is an embodiment of a chassis management module; and

FIG. 3 is an embodiment of an IPMI network in which an embodiment ofdeterministic chassis management module selection may be implemented.

DETAILED DESCRIPTION

Reference will now be made to embodiments of deterministic election of anode, examples of which are illustrated in the accompanying drawings.Moreover, those of ordinary skill in the art will appreciate that thedeterministic election of a node described in connection with a chassismanagement module may be applicable to other systems having redundantnodes. Other details, features, and advantages of deterministic electionof a node will become further apparent in the following detaileddescription of embodiments thereof.

Any reference in the specification to “one embodiment,” “a certainembodiment,” or a similar reference to an embodiment is intended toindicate that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. The appearances of such terms in various places in thespecification are not necessarily all referring to the same embodiment.References to “or” are furthermore intended as inclusive so “or” mayindicate one or another of the ored terms or more than one ored term.

A current version of Intelligent Platform Management Interface (IPMI)consists of three specifications: a specification for the IPMI, aspecification for an Intelligent Platform Management Bus (IPMB) that maybe utilized with the IPMI and a specification for an Intelligent ChassisManagement Bus (ICMB) that may also be utilized with the IPMI. Thosespecifications are available atdeveloper.intel.com/design/servers/ipmi/spec, as IPMI Specificationversion 1.5, Document revision 1.1, which was published Feb. 20, 2002.

The IPMI specification defines the messages and system interfaces toplatform management hardware. The IPMI standard further defines commoncommands, data structures, and message formats for interfaces in IPMI.IPMI also defines common management functions such as how a System EventLog and Sensor Data Records are managed and accessed, how the systeminterfaces work, how sensors operate, how control functions such assystem power on/off and reset are initiated, and how the IPMI hostsystem watchdog timer function operates.

The IPMB specification defines an internal management bus for extendingplatform management within a chassis. The IPMB typically is used to linkchassis management features with a motherboard management subsystem. TheIPMB Address specification specifies how devices are allocated addresseson an IPMB.

A certain IPMB is based on a 2-wire serial bus that provides astandardized interconnection between different devices, or boards, orblades within a chassis. The IPMB may also serve as a standardizedinterface for auxiliary devices.

The ICMB specification defines an external management bus betweenmultiple host systems and peripheral chassis.

IPMI defines common interfaces to certain hardware that is used tomonitor server physical characteristics, such as temperature, voltage,fan operation, power supply operation, and chassis integrity. Thosemonitoring abilities provide information that enables system management,failure recovery, and device monitoring. Management features mayinclude, for example, automatic alerting, automatic system shutdown andrestart, remote restart, and power control. Such abilities andflexibility have furthermore been found to result in lower cost ofoperation and more convenient operation.

IPMI may specify common, abstracted, message-based interfaces to amanagement micro-controller. That in turn may permit the isolation ofsoftware from hardware. IPMI may also specify commands and sensor datarecords that describe the number and type of monitoring and controlcapabilities of a platform. That allows software to discover andautomatically adapt to the monitoring and control features of theplatform.

Server Management may provide capabilities for server managementincluding, for example, high availability infrastructure that aims tokeep a system operational at all times, often through backup andfailover processing and data storage and access; electronic keying thatmay require replacement of a device with another device of the sameseries or revision to permit the device to work on a network; networkprovisioning systems that may provide customer services, logtransactions, carry out requests, and update files; fault tolerance;failure analysis; trending; and deployment of operating systems andsoftware.

Chassis management modules are nodes that may manage node operation inIPMI. It may also be desirable to have redundant nodes to perform suchhigh level management. Thus, it may be necessary to select which of twoor more chassis management modules are to act as an active chassismanagement module and which are to operate as standby chassis managementmodules. One or more shared storage nodes may also be coupled to theIPMI and may maintain information related to selection of an activechassis management module.

Each chassis management module may have a system identifier such as, forexample, a hardware address or an internet protocol address (IPaddress).

At power-up, an active chassis management module may be selectedrandomly or, for example, on the basis of an identifier of thosecommunicating chassis management modules with the idea that an initialactive chassis management module should be selected as soon as possibleat power-up and a more appropriate active chassis management module maybe selected within a short period of time thereafter.

Determination of a long-term active chassis management module may bebased, at least in part, on the state of each chassis management modulewhen that chassis management module was last energized. Various power-onor energization stages or modes may exist with chassis managementmodules. In one such mode, two or more chassis management modules areenergized and become operational nearly simultaneously. In such a mode,an active chassis management module may be selected from the variousoperational chassis management modules with minimal switching of activechassis management module between the operational chassis managementmodules.

In another mode, one or more chassis management modules is delayed inbeing powered or delayed in becoming operational due to, for example, afirmware upgrade. In such a mode, a predetermined time period may bepermitted to pass before selecting a chassis management module to beactive long-term, and after that predetermined time period a long-termactive chassis management module is selected from those chassismanagement modules that are available.

In yet another mode, a chassis management module may be swapped orremoved with another chassis management module put in its place during aperiod when the various chassis management modules are de-energized. Insuch a mode, if the chassis management module that was swapped was notactive at the time it was de-energized, no change need be made to theactive chassis management module at power-up, whereas if the chassismanagement module that was swapped was the active chassis managementmodule at the time when it was de-energized, then a standby chassismanagement module may be selected to become the active chassismanagement module at power-up.

When a chassis management module fails, if the failed chassis managementmodule is not active, no change need be made to the active chassismanagement module, whereas if the failed chassis management module isthe active chassis management module, then a standby chassis managementmodule may be selected to become the active chassis management module.

In an embodiment, the systems, apparatuses and methods described willoperate to minimize alternation of the active chassis management modulebetween two or more chassis management modules when those chassismanagement modules are energized. In those systems, apparatuses andmethods, if the chassis management module that was active when thechassis management modules were de-energized (the previously or lastactive chassis management module) is operational, that previously activechassis management module will resume as active chassis managementmodule when re-energized. If the previously active chassis managementmodule is not operational and only one other chassis management moduleis operational, then the operational chassis management module willbecome active. If more than one chassis management module isoperational, but none of the operational chassis management modules wasthe previously active chassis management module, then a new activechassis management module will be selected based on some criterion,which may be arbitrary, such as the chassis management module having thelowest globally unique identifier.

In an embodiment, the systems, apparatuses and methods will also preventthe active chassis management module from alternating between two ormore operational chassis management modules when direct communicationbetween two or more of those operational chassis management modules islost.

FIG. 1 illustrates an embodiment of a method deterministic chassismanagement module selection 100. That method 100 may activate a chassismanagement module or other node, or select a chassis management moduleor node to be activated, while minimizing re-activating or re-selectingof various chassis management modules or nodes available for activation.At 102, one or more chassis management modules are energized. After thechassis management modules are energized, hardware may be available todetermine the presence of chassis management modules and report thatinformation to operational chassis management modules. If such hardwareis available and only one chassis management module is present, thenthat chassis management module may be immediately selected to be active.

At 104, information may be retrieved from an active node record in theshared storage node by any energized chassis management modules. Thatinformation related to the chassis management module or modules may beread from a shared storage node coupled to a network communicating withthe chassis management modules and the network may be arranged so thatif a communication fault occurs between the chassis management modules,communication between the chassis management modules and the sharedstorage node may remain operational. That information retrieved from theshared storage node may include an identifier of the chassis managementmodule that was most recently active. Chassis management module globalidentifiers may be stored in various formats including a globally uniquehardware identifier (such as a serial number). The Internet Protocol(IP) is defined by the Internet Engineering Task Force (IETF) standard5, Request for Comment (RFC) 791 (referred to as the “IPSpecification”), adopted in September, 1981 and available fromwww.ieff.org.

If the information in the shared storage node may not be accessed, thenthe active chassis management module may be selected randomly or basedon its address. For example, the chassis management module having thelowest globally or system-wide unique identifier may be selected to beactive. One or more additional shared storage nodes may also be utilizedto store active chassis management module information and may providethat information to chassis management modules upon request when anothershared storage node is unable to provide that information.

At 106, if the chassis management module may communicate with the sharedstorage node and reads its own identifier as the previously activechassis management module, then the chassis management module may onceagain become the active chassis management module at 108.

At 110, the chassis management module determines whether it is able tocommunicate with other chassis management modules. That communicationmay be, for example, by way of the IPMB and may be by way of a routethat is different than the route with which the chassis managementmodule communicated with the shared storage node. As chassis managementmodules may not all begin to operate simultaneously, repeated attemptsto communicate may occur over a predetermined time period before anassumption is made that a non-responding chassis management module hasfailed.

At 112, if communication with another chassis management module that waspreviously active is successful, then that previously active chassismanagement module is elected to be active again at 114. If communicationwith other chassis management modules is successful, but no operationalchassis management module was the previously active chassis managementmodule then one of the operational chassis management modules may beelected to be active at 116. That election may be done arbitrarily or,for example, by electing the chassis management module having the lowesthardware address.

At 118, if the chassis management module is not able to communicate withanother chassis management module, because for example there is afailure of a portion of the IPMB, then the chassis management modulewill determine whether it was selected as active on power-up. Aspreviously discussed, at power-up, an initial active chassis managementmodule may be selected quickly and a more appropriate active chassismanagement module may be selected within a short period of timethereafter. At 118, if the instant chassis management module wasselected to be active at power-up, then at 120, that chassis managementmodule will write its identifier to the shared storage node, indicatingthat it is the current active node.

At 122, if the previously active chassis management module becomesoperational within an initial time limit of, for example, 35 seconds,then that previously active chassis management module may inform theinitial active chassis management module that it is taking over asactive chassis management module and the initial active chassismanagement module will become a standby at 124. That informing may occurby, for example, dedicated hardware signals that the CMM wishing tobecome active can toggle to convert from standby to active. Thosehardware signals may also indicate to another CMM that it is no longeractive. If the previously active chassis management module does notbecome operational within the time limit, then the instant chassismanagement module may write its global ID to shared storage and rewriteits system IDs to the shared storage node periodically, for example,every 15 seconds, to overwrite any other chassis management modules withwhich it cannot communicate. Then, at 126, after the initial time limitof, for example, 35 seconds, the instant chassis management module willbecome the active chassis management module.

At 118, if the chassis management module is not able to communicate withanother chassis management module and the chassis management module wasnot selected as active on power-up, then the chassis management modulewill write its system identifier to the shared storage node at 128 andmay perform that write a single time at 128 so that that identifier maybe overwritten as described above.

At 130, the chassis management module will check the shared storagenode, for example after the initial time limit runs out, and if theidentifier in the shared storage node has changed, then the chassismanagement module will remain a standby at 132, and if the identifier inthe shared storage node has not changed, then the chassis managementmodule will become active at 134.

It should be recognized that other chassis management modules that areoperational but cannot communicate with the previously active chassismanagement module may likewise utilize the method of selecting a chassismanagement module 100. Thus each chassis management module may writetheir addresses and then wait to determine if another chassis managementmodule overwrites its address, indicating that the overwriting chassismanagement module is the active chassis management module.

If information is available, for example through dedicated hardware,that indicates that only one chassis management module exists in thechassis, then that one chassis management module may be selected to beactive without performing the method of selecting a chassis managementmodule.

An active chassis management module may regularly transmit informationto one or more standby chassis management modules so that the standbychassis management modules will contain duplicate information thatmatches that in the active chassis management module. In that way, thestandby chassis management modules can seamlessly become active uponfailure or removal of the active chassis management module and have allappropriate information that the previously active chassis managementmodule contained.

Thus, the method for determination of an active chassis managementmodule 100 may reduce competition between chassis management modules andavoid a situation wherein, for example, two chassis management moduleseach attempt to repeatedly become the active chassis management module.

An article of manufacture that includes a computer readable mediumhaving stored thereon instructions that cause a processor to performthat method for determination of an active chassis management modulewhen those instructions are executed may also be constructed.

FIG. 2 illustrates a chassis management module 150. The chassismanagement module 150 includes memory 152, a processor 154, a storagedevice 156, an output device 158, an input device 160, and acommunication adaptor 162. It should be recognized that any or all ofthe components 152-162 of the chassis management module 150 may beimplemented in a single machine. For example, the memory 152 andprocessor 154 might be combined in a state machine or other hardwarebased logic machine.

Communication between the processor 154, the storage device 156, theoutput device 158, the input device 160, and the communication adaptor162 may be accomplished by way of one or more communication busses 164.It should be recognized that the chassis management module 150 may havefewer components or more components than shown in FIG. 2. For example,if output devices 158 or input devices 160 are not desired, they may notbe included with the chassis management module 150.

The memory 152 may, for example, include random access memory (RAM),dynamic RAM, and/or read only memory (ROM) (e.g., programmable ROM,erasable programmable ROM, or electronically erasable programmable ROM)and may store computer program instructions and information. The memory152 may furthermore be partitioned into sections including an operatingsystem partition 166, wherein instructions may be stored, a datapartition 168 in which data may be stored, and a chassis managementpartition 170 in which instructions for selection of a chassismanagement module and stored information related to such a chassismanagement module may be stored. The chassis management partition 170may also allow execution by the processor 154 of the instructions storedin the chassis management partition 170. The data partition 168 mayfurthermore store data to be used during the execution of the programinstructions such as, for example, active chassis management informationand information related to other nodes in the network.

The processor 154 may execute the program instructions and process thedata stored in the memory 152. In one embodiment, the instructions arestored in memory 152 in a compressed and/or encrypted format. As usedherein the phrase, “executed by a processor” is intended to encompassinstructions stored in a compressed and/or encrypted format, as well asinstructions that may be compiled or installed by an installer beforebeing executed by the processor 154.

The storage device 156 may, for example, be a magnetic disk (e.g.,floppy disk and hard drive), optical disk (e.g., CD-ROM) or any otherdevice or signal that can store digital information. The communicationadaptor 162 may permit communication between the processor based chassismanagement module 150 and other devices or nodes coupled to thecommunication adaptor 162 at a communication adaptor port 172. Thecommunication adaptor 162 may be a network interface that transfersinformation from nodes 201-207 on a network such as the network 200illustrated in FIG. 3, to the chassis management module 150 or from thechassis management module 150 to nodes 201-207 on the network 200. Thenetwork in which the chassis management module 150 operates mayalternately be a LAN, WAN, or the Internet. It will be recognized thatthe chassis management module 150 may alternately or in addition becoupled directly to one or more other devices through one or moreinput/output adaptors (not shown).

The chassis management module 150 may also be coupled to one or moreoutput devices 158 such as, for example, a monitor or printer, and oneor more input devices 160 such as, for example, a keyboard or mouse. Itwill be recognized, however, that the chassis management module 150 doesnot necessarily need to have any or all of those output devices 158 orinput devices 160 to operate.

The elements 152, 154, 156, 158, 160, and 162 of the chassis managementmodule 150 may communicate by way of one or more communication busses164. Those busses 164 may include, for example, a system bus, aperipheral component interface bus, and an industry standardarchitecture bus.

The network in which deterministic chassis management module selectionis implemented may be a network of nodes such as computers, dumbterminals, boards or blades in a chassis or other, typicallyprocessor-based, devices interconnected by one or more forms ofcommunication media. The communication media coupling those devices mayinclude, for example, twisted pair, co-axial cable, optical fibers andwireless communication methods such as use of radio frequencies.

Network nodes may be equipped with the appropriate hardware, software orfirmware necessary to communicate information in accordance with one ormore protocols. A protocol may comprise a set of instructions by whichthe information is communicated over the communications medium.Protocols are, furthermore, often layered over one another to formsomething called a “protocol stack.”

In addition to operating to select a chassis management module, in oneembodiment, selection of an active node and a standby node in a networksuch as an OSI based network may utilize the present method. The OSIarchitecture includes (1) a physical layer, (2) a data link layer, (3) anetwork layer, (4) a transport layer, (5) a session layer, (6) apresentation layer, and (7) an application layer.

The physical layer is concerned with electrical and mechanicalconnections to the network and may, for example, be performed by a tokenring or Ethernet bus in a standard OSI architecture. The data link layerarranges data into frames to be sent on the physical layer and mayreceive frames. The data link layer may receive acknowledgement frames,perform error checking and re-transmit frames not correctly received.The data link may also be performed by the bus handling the physicallayer. In the modified OSI architecture, IPMB may perform the physicaland data link layer functionality.

The network layer determines routing of packets of data and may beperformed by, for example, Internet Protocol (IP). The transport layerestablishes and dissolves connections between nodes. The transport layerfunction is commonly performed by a packet switching protocol referredto as the Transmission Control Protocol (TCP). TCP is defined by theInternet engineering Task Force (IETF) Standard 7, Request for Comment(RFC) 793, adopted in September, 1981 (the “TCP Specification”). Thenetwork and transport layers are often referred to collectively as“TCP/IP.”

In one embodiment, the network nodes utilize a packet switching protocolreferred to as the User Datagram Protocol (UDP) as defined by theInternet Engineering Task Force (IETF) standard 6, Request For Comment(RFC) 768, adopted in August, 1980 (the “UDP Specification”) inconnection with Internet Protocol (IP). The UDP Specification is alsoavailable from “www.ietf.org.”

UDP is a network communications protocol that offers lesser servicesthan TCP. For example, UDP may provide port numbers to distinguishdifferent user requests and a checksum to verify that data arrivedintact. UDP may, however, not provide sequencing of the packets orretransmission of unreceived packets. After the packets are created ineither UDP or TCP, the IP layer prepares the packets for transmissionacross a network such as the Internet.

The session layer establishes a connection between processes ondifferent nodes and handles security and creation of the session. Thepresentation layer performs functions such as data compression andformat conversion to facilitate systems operating in different nodes.The application layer is concerned with a user view of network data, forexample, formatting electronic messages. In certain TCP/IP platforms,the functionality of the session layer, the presentation layer, and theapplication layer are all performed by the application.

FIG. 3 illustrates an IPMI network 200 in which deterministic selectionof a chassis management module may be implemented. Node 1 201 and node 2202 may be chassis management modules. Node 3 203 may be a sharedstorage node. Node 4 204 and node 5 205 may be general purpose computersor client processors. Node 6 206 and node 7 207 may be IPMI nodes. Eachof those nodes 201-207 may be coupled to an IPMI network 200 with theshared storage node 203 coupled to each of the chassis managementmodules 201 and 202 separately from the coupling between the chassismanagement modules 201 and 202 for redundancy. Deterministic selectionof a chassis management module may be implemented in the chassismanagement modules 201 and 202 and active chassis management informationmay be stored in the shared storage node 203.

The shared storage node 203 may include a processor, a data storagedevice and a network adaptor similar to the processor 154, storagedevice 156, and communications adaptor 162 discussed in connection withFIG. 2. The shared storage node 203 may operate as discussed inconnection with the method of selecting a chassis management module 100discussed in connection with FIG. 1. The data storage device mayfurthermore receive, contain and transmit information related to a lastactive chassis management module. The processor may receive theinformation related to the last active chassis management module from achassis management module, store that information in the data storagedevice, and retrieve that information from the data storage device whenrequested to do so by a chassis management module. The network adaptormay transmit the information to and from the shared storage node 203.

While the systems, apparatuses, and methods of deterministic selectionof a chassis management module have been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof. Thus, it isintended that the modifications and variations be covered provided theycome within the scope of the appended claims and their equivalents.

1. An active node selection method, comprising: selecting the activenode based on information stored in a storage node where available; andselecting the active node based on an identifier of an available nodewhere information stored in the storage node is not available.
 2. Theactive node selection method of claim 1, wherein the selection is madebetween at least two nodes capable of operating as the active node. 3.The active node selection method of claim 1, wherein the storage nodeand the active node are coupled to a common network.
 4. The active nodeselection method of claim 1, wherein the information is read from thestorage node and includes an identifier of a previously active node. 5.The active node selection method of claim 4, wherein the previouslyactive node is the node that was active prior to de-energization of theactive node if the information stored in the storage node indicates thepreviously active node when the previously active node is energized. 6.The active node selection method of claim 1, wherein the identifier isan address of the node.
 7. The active node selection method of claim 1,wherein the information stored in the storage node includes a globallyunique identifier associated with a last active node.
 8. The active nodeselection method of claim 1, further comprising selecting the activenode based on communications between at least two nodes where suchcommunication is possible, and wherein selecting the active node basedon information stored in a storage node occurs when communicationbetween the two nodes is not possible.
 9. A node activation method,comprising: determining whether one or more other nodes that may becomeactive are coupled to the node. reading an identifier from a sharedstorage node; activating the node if the identifier indicates the node;selecting one of the node and the other nodes as initially active if thenode and the other nodes are not indicated by the identifier read fromthe shared storage node; writing an identifier of the node to the sharedstorage node if the node and the other nodes are not indicated by theidentifier read from the shared storage node; rewriting the identifierof the node to the shared storage node periodically if the node isinitially active; and selecting the node as active if the identifier ofthe node remains in the shared storage node after a predetermined periodof time and a last active node has not informed the node that it isactive within the predetermined period of time.
 10. The node activationmethod of claim 9, wherein a hardware device external to the nodedetermines the presence of network nodes and reports present networknodes to the node.
 11. The node activation method of claim 9, whereinre-writing the identifier of the node to the shared storage node occursafter re-reading the identifier from the shared storage node and whenthe identifier from the shared storage node is not the identifier of thenode.
 12. The node activation method of claim 9, further comprisingcommunicating with the one or more other nodes that could become activeand are coupled to the node and selecting an active node from among thenode and the other nodes based on activity prior to the node and one ormore other nodes that could become active last being de-energized. 13.The node activation method of claim 9, wherein the node and the othernodes are coupled to a common network.
 14. The node activation method ofclaim 9, wherein the identifier is a globally unique identifier.
 15. Thenode activation method of claim 9, wherein the identifier is a systemunique identifier.
 16. The node activation method of claim 9, whereinthe one of the node and the other nodes that is selected as initiallyactive is the one of the node and the other nodes having a lowestidentifier value.
 17. The node activation method of claim 9, wherein theone of the node and the other nodes that is selected as initially activeis the one of the node and the other nodes having a highest identifiervalue.
 18. A chassis management module, comprising: a communicationsadaptor to couple to a network; a processor to retrieve active chassismanagement module information from a shared storage node through thecommunications adaptor, attempt to communicate with other chassismanagement modules coupled to the network through the communicationsadaptor, and determine whether the chassis management module should beactive based on the information and the communication.
 19. The chassismanagement module of claim 18, wherein the active chassis managementmodule information includes an address of a last active chassismanagement module and the chassis management module is to become activeif an address of the chassis management module matches the address inthe information.
 20. The chassis management module of claim 18, whereinthe processor is further to become initially active if the chassismanagement module and the other chassis management modules coupled tothe network are not indicated by the information retrieved from theshared storage node.
 21. The chassis management module of claim 20,wherein one of the other chassis management modules is to become activeand the chassis management module is not to become active if the chassismanagement module has an identifier that is greater than one of theother chassis management modules.
 22. The chassis management module ofclaim 20, wherein one of the other chassis management modules is tobecome active and the chassis management module is not to become activeif the chassis management module has an identifier that is less than oneof the other chassis management modules.
 23. The chassis managementmodule of claim 20, wherein the processor is further to: write anidentifier of the chassis management module to the shared storage nodeif the chassis management module and other chassis management modulesare not indicated by the information retrieved from the shared storagenode; rewrite the identifier of the chassis management module to theshared storage node periodically if the chassis management module isinitially active; and select the chassis management module as active ifthe identifier of the chassis management module remains in the sharedstorage node after a predetermined period of time and a last active nodehas not informed the node that it is active within the predeterminedperiod of time.
 24. A node, comprising: a network adaptor to receive andtransmit information related to a last active chassis management module;and a data storage device to store the information.
 25. The node ofclaim 24, wherein the data storage device is to receive the informationrelated to the last active chassis management module through the networkadaptor from a chassis management module.
 26. The node of claim 24,wherein the data storage device is to transmit information related tothe last active chassis management module to a chassis management moduleby way of the network adaptor when the information is requested by thechassis management module.
 27. An article of manufacture, comprising: acomputer readable medium having stored thereon instructions which, whenexecuted by a first processor, cause the first processor to: retrieveactive processor information from a shared storage node; become activeif the active processor information indicates the first processor;attempt to communicate with a second processor indicated by the activeprocessor information if the active processor information does notindicate the first processor; and become active if the second processordoes not communicate with the first processor.
 28. The article ofmanufacture of claim 27, wherein becoming active further comprises theinstructions causing the first processor to: writing the identifier ofthe node to the shared storage node periodically; and selecting the nodeas active if the identifier of the node remains in the shared storagenode after a predetermined period of time and a last active node has notinformed the node that it is active within the predetermined period oftime.
 29. A network comprising: a shared storage node coupled to anetwork to receive active chassis management module information, tostore such active chassis management module information, and to transmitsuch active chassis management module information when requested; and achassis management module coupled to the network to request activechassis management module information from the shared storage node andtransmit information related to the chassis management module to theshared storage node when the chassis management module becomes active.30. The network of claim 29, wherein the active chassis managementmodule information includes an identifier of the last active chassismanagement module.